suspects were told killed a police officer last night, a campus officer for the massachusetts institute of technology. this is that police officer, sean collier, 26 years old was shot to death in his police cruiser after midnight. he had been on the force about a year. after the that the suspects hijacked a car, threw the driver out unharmed, thread police on a chase through the northern suburbs of boston throwing bombs out of the car, gunfire as well on the pursuing officers, the car came to a halt for reasons we do not know. a fire fight ensued at that location, more bombs were thrown 200 rounds of ammunition was expended. the elder brother, tamerlan tsarnaev was killed that that fire fight but the younger brother, dzhokhar, 19 years old, escaped on foot. no sign of him since until perhaps this moment. what we're waiting to find out is whether, indeed, the police and the f.b.i. have found the suspect that they've been searching for so diligently all day long. john miller? >> it's interesting scott was this was for a swat team search for a suspect, an unusually large perimeter. this was a 20-block p